Redundant Power Module for Substation Protection
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Solution Overview
Problem
Electric power delivery systems face protection failures due to interruptions in operational power, which can occur from DC faults, battery charger failures, or maintenance incidents, leading to loss of availability for protective devices.
Innovation Solution
A redundant power module that receives power from multiple sources, conditions it, and stores energy to continuously provide operational power to critical equipment like protective relays and IEDs, even during disruptions or loss of all power sources, using capacitive elements for power storage and active circuitry for power conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If operational power is obtained from a single source, then the system is simpler, but protection devices fail during power interruptions
Solution Approach 1:
The patent combines multiple power sources (DC power source, AC power sources from different phases, and power storage device) into a unified power supply system. The power conversion circuit integrates rectification from AC sources and regulation from DC source, merging them into a common output that supplies protective devices. This merging ensures continuous power availability while maintaining system reliability.
Solution Approach 2:
The power storage device (capacitor bank) is pre-charged during normal operation from available power sources. When power interruption occurs, the pre-charged storage device immediately supplies power to protective devices, enabling ride-through capability. This preliminary charging action ensures no gap in power supply to critical protection functions.
2Reliability
If multiple power sources are used, then power availability improves, but system complexity increases
Solution Approach 1:
The power conversion circuit is designed to universally accept power from multiple sources (DC from battery charger, AC from any phase) and convert them to a common output format suitable for protective devices. The circuit performs multiple functions: rectification of AC inputs, regulation of DC input, and unified output provision. This multi-functionality reduces the need for separate conversion circuits for each power source.
Solution Approach 2:
The power storage device (capacitor bank) acts as an intermediary between multiple power sources and the protective devices. It buffers and smooths power from various sources, providing a stable unified output. The storage device mediates the integration of different power sources, simplifying the overall system architecture by providing a single point of power delivery to loads.
3Duration of action of moving object
If power storage capacity is increased, then ride-through capability improves, but device size and cost increase
Solution Approach 1:
The power storage device is sized to provide partial power support during interruptions, specifically designed to maintain operation of critical protective devices (relays, trip coils) for a limited duration. Rather than providing excessive capacity for all substation loads, the system implements selective power support for essential protection functions, achieving adequate ride-through capability with minimal storage capacity.
Solution Approach 2:
The power storage system provides differentiated power support to different loads based on their criticality. Protective devices receive priority power support from the storage device during interruptions, while non-critical loads may be shed. This local quality approach ensures that limited storage capacity is allocated to where it provides maximum safety value, optimizing the balance between storage size and protection reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures reliable operation of protective devices and systems by maintaining power supply during disruptions, allowing for ride-through of temporary power outages and enabling continuous protection of the electric power delivery system.
Implementation Method 1
A power storage device, such as a capacitor bank, may be included to provide continuous power to devices during an interruption of power from all power sources.
Implementation Method 2
The multiple AC and DC power sources may be passed through power conversion circuitry to provide a single DC output.
Data Source
AI summary
Disclosed herein are systems for maintaining protection of electric power delivery systems in the event of a control power failure or other anomaly. A reliable power module conditions electric power from multiple independent sources and provides electrical operational power to electric power delivery system protective loads. The reliable power module includes a power storage device for providing operational power even upon loss of all control power sources. The power storage may be sufficient to ride through expected losses such as a time to start up backup generation. The power storage may be sufficient to power a trip coil. Thus, electric power system protection is maintained even upon loss of control power.